Mississippi River

Bottomlands, Levees, Estuaries, Gulf Hypoxia

Michael Pohlmann, Chad Ketcham, Phillip Tilson, Bradley Schmitz

Bottomlands/Floodplains

• Low-lying forested and marsh areas extending away from a river or stream. Subjected to periodic flooding.

• Historically extremely biodiverse.

• Critical habitat for numerous species of bird and amphibians. (perhaps most threatened)

Ecological Challenges

• Agriculture- nutrient runoff, Ag-chemical, soil erosion, physical destruction of habitat

• Industry- dumping, transportation requiring channel manipulation and extensive lock/dam system.

• Hydrologic control- levees, lock/dam systems, canals, settling basins.

Restoration

• Restoration is slow and complex.

• Large-scale planting efforts, restoring some natural hydrologic systems, ID of threatened endangered plant & animal species.

• Best approaches are multi-facetted:– Establishment of refuges– Planting Efforts– Reintegrating hydrologic and nutrient cycles (allowing

natural floods to occur)

Sunset Marina, Rock Island IL

What are Levees?

“A manmade barrier (embankment, floodwall or structure) along a watercourse constructed for the primary purpose to provide hurricane, storm, and flood protection relating to seasonal high water, storm surges, precipitation and other

weather events; and that normally is subject to water loading for only a few days or weeks during a year”.

(http://www.leveesafety.org/ip_leveedefinition_22March11.cfm)

http://islandbreath.org/2007Year/08-technology/0708-06HanapepeLevee.jpg

http://img.search.com/thumb/6/69/Sacramento_River_Levee.jpg/400px-Sacramento_River_Levee.jpg

http://www.cement.org/water/images/slurry_levee.jpg

Levees and the Mighty Mississippi…• The main stem levee system is 2,203 miles

long. (Along with thousands of miles of side channels.)

• The levees are constructed by the feds and maintained by local interest groups.

• Periodic inspections are performed by the Army Corps of Engineers.

http://www.mvn.usace.army.mil/pao/bro/misstrib.htm

Levees and Natural Wetlands…

• As we have seen a levee separates the river from the surrounding land.

• Wetlands could possibly dry up.

• Native plants and animals disappear. • Soil no longer gets the nutrients it needs from the

main river which in turn causes invasive non-native plants to take hold.

Estuaries of Louisiana

WHAT IS AN ESTUARY???• Estuaries are bodies of water that are located where rivers

meet the sea.

• Contain a diversity of plants and animals due to brackish water, ( mixture of freshwater from land and salty seawater).

• One of the most productive ecosystems in the world. Provide food, nesting, breeding, jobs, recreation and housing.

• Of the 32 largest cities in the world, 22 are located in estuaries, ex , New York and New Orleans.

Problems of Louisiana Estuaries

• Pathogens

• Toxic Substances

• Changes in Living Resources

• Eutrophication

• Habitat Loss

• Sediment Reduction

Importance• Environmental- provide habitats for amphibians,

reptiles, birds, fish, insects, and other wildlife.

• Economic-recreation, fish market, transportation, housing and tourism

• Ecosystem- habitat protection and water filtration.

What is Being Done• BTNEP (Barataria-Terrebone National Estuary

Program)

• Designed to conserve, restore and protect the current Louisiana Estuaries.

Gulf of Mexico’s “Dead Zone”• Region is so depleted of oxygen

that marine organisms are killed or driven away.

• Hypoxia – low concentrations of dissolved oxygen in the bottom of waters

• Aquatic animals obtain oxygen by respiring through gills.

• Low concentrations of oxygen

cause animals to asphyxiate.

Causes

•Nitrogen, Phosphorous, and nutrients are flushed down the Mississippi River and Atchafalaya River into the Louisiana Coast.

• Fertilizers, urban runoff, industrial discharges, fossil fuel emissions, and municipal sewage outflow pollute the River and are deposited in the Gulf of Mexico.

Eutrophication1.) Enhancing the amount of nitrogen increases the growth of phytoplankton (photosynthetic algae), protists, and cyanobacteria that drift near the surface.

2.) Zooplankton consume large amounts of phytoplankton. The waste products and dead phytoplankton drift to the bottom of the ocean floor.

3.) Bacteria decomposers consume the dead organic matter. Bacteria populations increase and cause oxygen concentration in the water to decrease significantly as the bacteria consume oxygen.

4.) Low concentrations of oxygen suffocate shrimp and fish creating the “Dead Zone.”

Eutrophication

ProblemsFisherman and Coastal Economies• 72% of U.S. harvested Shrimp• 66% of U.S. harvested Oysters• 16% of U.S. Commercial fish

Loss of Biodiversity

Toxicity of Algae Blooms – Neurotoxins and Hepatotoxins kill animals and pose threat to humans• Shellfish take up toxins, then humans eat shellfish leading to paralytic, neurtoxic, and/or diarrhoetic shellfish poisoning

Solutions• Use fewer fertilizers• Limit runoff from farms• Change Cropping systems and timing • Switch from traditional crops (corn/ soybean) to alternatives• Monitor Septic Systems and Sewage Treatment• Limit Discharges of nutrients, organic matter, and chemicals from facilities• Human made Wetlands and Riparian Buffers• Flood Control• Mississippi River diversions• Biosurfactants (Soap from bacteria)

Works Cited

• http://oceanservice.noaa.gov/education/tutorial_estuaries/est03_ecosystem.html

• http://oceanservice.noaa.gov/education/tutorial_estuaries/est02_economy.html

• http://www.epa.gov/owow_keep/estuaries/pivot/2009barataria_terrebonne.html

• “Status, Trends, and Probable Causes of Change in Living Resources in the Barataria-Terrebonne Estuarine System.” Publication #21 BTNEP. 1996. Condrey, Kemp and Visser.

• “Healthy Estuary, Healthy Economy, Health Communities.” BTNEP. 2002, Thibodaux, LA.

Works Cited Cont.• ”Dispersing Oil the Natural Way, Using Biosurfactants and Resident Marine

OrganismsEcology Today: Ecology News, Information & Commentary Blog." The Ecology Global Network | Ecology News and Information for Residents of Planet Earth. Web. 19 Sept. 2011. <http://ecology.com/ecology-today/2010/07/12/dispersing-oil-the-natural-way-using-biosurfactants-and-resident-marine-organisms/>.

• Diaz, Robert J. "Spreading Dead Zones and Consequences for Marine Ecosystems." Science 321 (2008): 926. Sciencemag.org. Science AAAS. Web. 11 Sept. 2011. <http://www.sciencemag.org.ezproxy2.library.arizona.edu/content/321/5891/926.full>.

• "The Gulf of Mexico Dead Zone." SERC. Web. 19 Sept. 2011. <http://serc.carleton.edu/microbelife/topics/deadzone/>.

• Mitsch, William J. "Reducing Nitrogen Loading to the Gulf of Mexico from the Mississippi River Basin: Strategies to Counter a Persistent Ecological Problem." Bioscience 51 (2001): 373-88. JSTOR. Web. 11 Sept. 2011.